This invention relates to apparatus for repairing a pipeline and method for using same.
One method of repairing damaged sewer pipe is to excavate the area surrounding the sewer pipe and replace the broken portion. This is a very expensive and labor intensive solution and is also an inconvenience to residents living in the area and utilizing roadways overlying the area.
Another solution is in situ relining of sewer pipes. In situ methods typically utilize a resin coated liner which is inserted into the existing sewer pipeline and unrolled against the sewer pipe. The unrolled liner is held against the existing sewer pipe while the resin cures to form a new pipe lining within the existing pipe.
One example of such a method is shown in U.S. Pat. No. 4,366,012 dated Dec. 28, 1982. In this patent is shown a process utilizing an elongated outer tube having an inner tube comprised of felt. Uncured resin is introduced into the tube and is used to impregnate the felt inner tube. The two concentric tubes are then inverted into the end of the sewer pipe to be repaired and the inversion process continues until the area of the sewer pipe needing repair has been reached by the inverting tubes. Upon inversion the impregnated felt liner is placed on the outside of the original outer liner, and is pressed against the interior surface of the sewer pipe. When the resin cures a new pipe liner is provided at the area to be repaired.
U.S. Pat. No. 4,366,012 shows a method for impregnating the inner felt tube with uncured resin. The impregnation is initiated by pouring the uncured resin in one end of the two concentric tubes. A slit is made in the outer tube approximately 12 inches from the other end of the outer tube. A vacuum cup is placed over the slit and a vacuum is drawn from the outer tube, thereby causing flattening of the outer tube and assisting the resin to spread through the fabric liner and impregnate it from one end to the other. Once the resin has impregnated the entire felt liner the vacuum is shut off and a patch is solvent welded over the slit.
There are several disadvantages to this impregnation process. The slit makes the outer tube or bladder weaker. Furthermore the cutting of a slit and the patching of a slit are time consuming. If the removal of the vacuum source from the vacuum cup is not timed properly, the vacuum cup will suck up some of the resin, thereby rendering the vacuum equipment inoperable.
Another disadvantage of the method of repairing a sewer pipe shown in U.S. Pat. No. 4,366,012 is that the outer bladder and the inner felt tube must be inverted into the sewer pipe beginning at a manhole located nearest to the area to be repaired. The inverted tubes must then extend to the area to be repaired, thereby requiring a length of tube which will reach from the nearest manhole to the area to be repaired.
For example, if a 300 foot long liner is required, the method of U.S. Pat. No. 4,366,012 requires pouring resin at one end of the tube, moving down the tube for approximately 50 feet, making a slit in the coating of the fabric liner, placing a suction cup over the slit, drawing the resin to that point, removing the vacuum, and placing a patch over the slit. Then it will be necessary to move another 50 feet down the tube and repeat the process. This process will continue at approximately 50 foot intervals until the desired location on the tube is reached.
The foregoing 50 foot intervals are necessary because it is only possible to draw a vacuum so far down the tube and still be effective.
Another disadvantage of the method shown in U.S. Pat. No. 4,366,012 is that the fabric liner is coated. In some applications, it would be desirable to utilize a liner that is not coated and instead use a liner that is separate from the bladder.
Most of the sewer mainlines are usually located in roadways and are buried at a considerable depth. These mainlines have lateral pipes that branch off to houses, businesses and industries. Lateral lines are conduits for carrying waste from these houses, businesses and industries out to the mainline sewer.
Mainline sewers are typically straight with access manholes at spaced apart positions along the length of the main sewer line. Mainline sewers are usually owned by municipalities or utility companies who utilize the services of civil or professional engineers for the design of sewer installations, inspections, and final work acceptances.
Lateral sewers on the other hand are typically installed by local plumbers or home owners. It is common to find numerous bends or fittings in a lateral sewer as well as inappropriate materials used in the original construction. These lateral installations offer a greater challenge in repair than do the reconstruction of the straight and professionally designed mainline sewers.
Therefore, a primary object of the present invention is the provision of an improved apparatus for repairing a pipeline and method for using same.
It is another object of the present invention to provide an apparatus for the insertion and installation of a new liner into an existing pipe which is particularly suitable for the spot repair of damaged sections of a given pipeline, wherein the liner is introduced into the existing pipe by means of a carrier which encloses the liner and protects it from contact with the surrounding pipe walls until the liner is in its desired location within the existing pipe.
It is a further object of the present invention to provide a method for relining pipes in which the pipe liner is secured to an inflation bladder, impregnated with resin and encapsulated within a positioning element, the positioning element then being inserted into an existing pipe and fluid being introduced under pressure into the positioning element to cause the inflation bladder and the liner secured thereto to invert outwardly from within the positioning element to a placement position near the compromised pipe section, the inflation bladder expanding radially in response to fluid pressure and urging the liner into contact against the pipe wall, and subsequently removing the inflation bladder and positioning the element from the pipe.
A further object of the present invention is the provision of an improved method for impregnating a resin absorbent material with an uncured resin while the resin absorbent material is within an inflatable bladder tube.
A further object of the present invention is the provision of an improved method for repairing lateral sewer pipe and particularly for repairing the juncture between the lateral sewer pipe and the mainline sewer pipe.
A further object of the present invention is the provision of an improved carrier which is integral with the bladder tube, and which permits the positioning of the bladder tube within the sewer pipeline in the general area of the pipeline to be needing repair.
A further object of the present invention is the provision of a method for repairing sewer pipeline wherein the outer carrier is disposable after use.
A further object of the present invention is the provision of an improved method and apparatus for repairing pipeline which is economical in manufacture, durable in use, and efficient in operation.
The foregoing objects may be achieved by an elongated bladder tube having a fill end for receiving a quantity of fluid resin, a vacuum end for connection to a vacuum source, and flexible tube walls forming a tube cavity therein. A layer of resin absorbent material is within the tube cavity and includes first and second material ends. The first material end is spaced a predetermined distance from the vacuum end of the bladder tube. An elongated wick includes an interior wick end positioned between the first and second material ends of the resin absorbent material. The wick extends from its interior wick end toward the vacuum end of the bladder tube and terminates in a vacuum wick end with at least a portion of the wick being located between the vacuum end of the bladder tube and the second material end of the resin absorbent material.
One modified form of the above apparatus involves the use of an elongated carrier which is separate from the bladder tube and which contains the bladder tube and the tube of resin impregnated material so as to protect them during insertion into a sewer pipeline. When the carrier is located adjacent the area in the pipeline to be repaired, the bladder tube is inverted out of the carrier tube and this places the resin impregnated material in contact with the sewer pipe walls needing repair.
Another modified form of the present invention utilizes a carrier which is integral with the bladder tube, and which is folded back on the bladder tube so as to create an outer carrier tube in protective relation over the bladder tube.
The present invention also involves a new method for impregnating a curable resin in a layer of resin absorbent material located within an elongated flexible bladder tube having a fill end and a vacuum end positioned down stream from the fill end. The bladder tube includes tube walls forming a tube cavity therein. The layer of resin absorbent material has a down stream end positioned a predetermined distance from the vacuum end of the bladder tube and an upstream end. An elongated gas conduit having first and second conduit ends is placed within the tube cavity with the first conduit end positioned upstream from the down stream end of the resin absorbent material and with the second conduit end positioned downstream from the downstream end of the resin absorbent material.
The new method involves introducing a quantity of curable resin into the fill end of the bladder tube, the quantity of resin being sufficient to impregnant all of the resin absorbent material within the bladder tube. A vacuum source is then connected to the bladder tube at a point spaced downstream from the downstream end of the resin absorbent material whereby the wall of the bladder tube will collapse on the layer of resin absorbent material and the gas conduit will provide a path for evacuating gas through the collapsed tube walls. Gas is continuously evacuated from the bladder tube until the curable resin moves to the downstream end of the absorbent material and completely impregnates the absorbent material.
While the gas conduit may take a variety of forms without detracting form the invention, the preferred form is an elongated air permeable wick. However, other forms such as tubes, hoses, or other types of conduits may be used for evacuating the air and gas through the collapsed tube walls.
Another aspect of the present invention is the provision of a method for repairing the junction between a lateral sewer pipe and a mainline sewer pipe. The method involves taking a preliner tube (preferably a thermoplastic tube) having first and second ends and being sized to fit within the lateral sewer pipe. The preliner tube includes an open cell gasket extending around the interior surface adjacent one end thereof. The open cell gasket is impregnated with an uncured grout. While different types of grout may be used without detracting from the invention, an example of a preferred grout is a chemical hydrophillic grout manufactured by Thane-Coat Company in Houston, Tex. under the product name TC-2400. The preliner tube is then inverted into the lateral sewer pipe to a position wherein the open cell gasket impregnated with grout is now on the exterior of the preliner and positioned at the juncture between the lateral sewer pipe and the main line sewer pipe. The gasket impregnated with grout forms a water tight seal between the preliner tube and the main sewer pipe and the lateral sewer pipe.
Next a flexible sleeve is inserted inside the preliner tube, the sleeve being impregnated with uncured resin. The sleeve may be made of any material capable of absorbing the uncured resin, but a fabric sleeve is preferred. Fluid pressure is applied inside the sleeve to force the sleeve radially outwardly against the preliner until the uncured resin cures and hardens.
The preferred method for placing the preliner tube in the lateral sewer pipe is by the inversion method described above. Similarly the preferred method for inserting the flexible sleeve into the preliner tube is by the inversion method described above.
Another method for repairing a lateral sewer pipe which joins a main sewer pipe at a pipe junction involves taking a preliner assembly comprising a preliner bladder tube and a preliner sleeve within the preliner bladder tube. The preliner sleeve is impregnated with an uncured first material capable of curing and expanding. While different materials may be used, a preferred material is the chemical hydrophillic grout referred to above. Next the preliner assembly is inverted into the lateral sewer pipe whereby the preliner sleeve will be outside and surrounding the preliner bladder tube. A second liner assembly is formed comprising a second bladder tube and a second sleeve within the second bladder tube. The second sleeve is impregnated with an uncured second material capable of curing and hardening. This second material may vary without detracting from the invention, but it is preferred that a curable resin be used. The second liner assembly is then inverted into the preliner tube whereby the second sleeve will be outside the second bladder tube and the preliner bladder tube will be between the preliner sleeve and the second sleeve. The second preliner tube is expanded radially outwardly so as to hold the second sleeve, the preliner tube, and the preliner sleeve against the lateral sewer pipe. The second sleeve is permitted to cure and harden and then the second bladder tube is removed. The preliner bladder tube forms a moisture impervious layer between the preliner sleeve and the second sleeve. The grout within the preliner sleeve is forced radially outwardly into any open joints, fractures or holes in the host lateral pipe. The grout is activated by water and expands and reinforces the waterproof properties of this system. Once the procedure is complete the liners protruding within the main line are cut off by using a robotic cutter.
Another method for repairing a lateral sewer pipe which joins a main sewer pipe at a pipe junction involves forming a main/lateral liner assembly having an elongated main liner tube and an elongated lateral liner tube. The main liner tube has first and second main liner tube ends and the lateral line tube has a first lateral liner tube end connected to the main liner tube and has a second lateral liner tube end. The main/lateral liner tube assembly is formed from a felt material having a urethane coat or similar material on its outer surface.
The main liner tube is then impregnated and the lateral liner tube is also impregnated with an uncured material capable of curing and hardening. The main/lateral liner assembly is then moved through the main sewer pipe to an operative position with the main liner tube adjacent the pipe junction and with the lateral liner tube extending within the lateral sewer pipe. Next, a lateral bladder tube is inserted into the lateral liner tube and is spread radially outwardly to press the lateral liner tube against the lateral sewer pipe until the uncured material cures and hardens. Then, a main bladder tube is inserted into the main liner tube and is spread radially outwardly to press the main liner tube against the main liner sewer pipe until the uncured material cures and hardens. The lateral and main bladder tubes are then removed leaving the repaired pipe.